This invention relates to nozzles for nitrous oxide systems for internal combustion engines, and, more particularly, to a nozzle design that promotes enhanced atomization of the fuel to boost combustion efficiency of the nitrous oxide and fuel mixture and increase the horsepower generated by the engine.
In a conventionally fueled internal combustion engine, vaporized fuel, typically either gasoline or alcohol, introduced through a carburetor mixes with outside air drawn into the engine manifold to form a combustible mix. That combustible mix, as example, is drawn from the intake manifold, through an intake runner of the manifold and into a cylinder of the engine. The combustible mix is ignited, typically, by an electric spark produced by a spark plug of the ignition system for the engine. The resultant explosion in the engine cylinder drives the piston, producing the mechanical force that is ultimately transferred to the wheels of the automobile. The foregoing combustion process repeats for each cylinder in the engine. The proportion of oxygen in a given volume of air relative to the other components of the air, such as nitrogen, is relatively fixed. Typically, through proper carburetion, the ratio of oxygen and fuel in the mixture, is set to the optimal ratio that is known to achieve the most efficient explosion.
To enhance performance of internal combustion engines in automotive racing application beyond that possible from conventional fuel systems, it has been known to inject nitrous oxide (xe2x80x9cN2Oxe2x80x9d) into the cylinder along with the combustible mix introduced by the carburetor and to accompany the nitrous with an injection of additional fuel. The apparatus for doing so are known as nitrous oxide systems. The nitrous oxide system introduces nitrous oxide and fuel to accompany the mixture of fuel and external air from the carburetor to form a highly combustible mixture that is drawn into the engine manifold, and, thence, into the engine cylinders. When heated to elevated temperatures of 572 degrees F or so, available within the engine, the nitrous oxide decomposes into molecules of nitrogen and oxygen. In that way oxygen is added to that oxygen introduced through the carburetor, enriching the combustible mix in the cylinders.
The addition of only nitrous oxide to the combustible mix leans out the mix and would quickly result in overheating the engine resulting in engine damage. To avoid that heating, fuel is injected along with the nitrous to effectively enrich the mixture, maintaining a lower temperature in the engine cylinders. Typically, the amount of fuel added is significantly less than the volume of the added nitrous oxide, but the exact proportion remains the judgement of the drag racing enthusiast.
The combustible mixture produced is more powerful than before, and as a result the engine produces greater horsepower. Because the nitrous oxide contains proportionally much more oxygen molecules, when mixed with the added fuel, a more powerful explosion is produced on ignition. The nitrous oxide effectively enriches the combustible mixture. Compared to other techniques for increasing engine horsepower, the nitrous oxide technique accomplishes that increase at minimal expense.
Nitrous oxide is stored in a canister carried by the vehicle. The stored nitrous oxide is under high pressure that maintains the nitrous oxide in a liquid state. A plumbing system, including conduit and solenoid valves, extends from the storage canister to the engine intake manifold. That plumbing system and an associated plumbing system for the fuel are each coupled to a number of nozzles, each of which is associated with a respective cylinder of the multi-cylinder engine. Each nozzle contains separate passages for the nitrous oxide and the fuel. Through the nozzle, both the fuel and the nitrous oxide are introduced into the region of the intake manifold runners, where both are mixed together and drawn through the intake manifold, cylinder head, and into the cylinders.
Honed by competition, racing enthusiasts have sought to squeeze greater power from engines employing nitrous oxide systems. Most often the search for improvement is accomplished through. xe2x80x9chands-onxe2x80x9d trial and error in the field and/or application a xe2x80x9csixth sensexe2x80x9d of what to adjust or change, not by academia. Shaving a few fractions of a second from the time required to race a vehicle down a quarter-mile racetrack, though small in the absolute sense, is very significant to the enthusiast. Considerable time, effort and money is expended to achieve such improvements. As often said, no one remembers the person who placed second in a race.
One area of improvement has been the nozzle. One nozzle design in a nitrous oxide system is presented in U.S. Pat. No. 5,699,766 to Wood et al., granted Dec. 23, 1997, entitled Nozzle for Mixing Oxidizer With Fuel (hereafter the xe2x80x9c""766 Wood patentxe2x80x9d). In that design, the nitrous oxide stream under high pressure is expressed from a bowl shaped outlet at high velocity, changing state to a gas. From that outlet the nitrous oxide stream is directed into a mixing bowl region formed in the tip end of the nozzle adjacent the nitrous oxide outlet. A stream of fuel, pumped at conventional pressures, typically 5 psig, is expressed directly into the mixing bowl, where the fuel stream intersects, is impacted and atomized by and mixes with the stream of high pressure nitrous oxide gas. According to the Wood patent, the high velocity N2O stream creates a low pressure at the fuel outlet that assists to draw fuel from the fuel outlet. Nozzles constructed in accordance with the foregoing design have produced good results over the predecessor techniques and that nozzle achieved wide acceptance among racing enthusiasts.
Another nozzle design is presented in U.S. Pat. No. 5,890,476, granted Apr. 6, 1999 to Grant. The design provides for a wing-shaped nozzle body to aerodynamically modify movement of the airstream from the carburetor about the nozzle body. Further, in the Grant design, the nitrous oxide stream flows from a bell shaped outlet and passes by the front end of an adjacent U-shaped recess in and at the front end of the nozzle into which a stream of fuel is expressed from the conduit. The venting fuel stream is said to intersect the nitrous stream in front the bell shaped nitrous port. The foregoing nozzle design, like that of the ""766 Wood patent, appears to rely upon the stream of nitrous oxide to both atomize the fuel and mix with that atomized fuel for entry into an intake manifold.
Although the foregoing nozzles of the foregoing Wood and Grant patents appear to provide appropriate atomization of the fuel and the mixing necessary to produce combustion, applicant has discovered that better atomization of fuel and intermixture of fuel and nitrous oxide is capable of extension beyond that which is possible from the foregoing nozzle designs.
Accordingly, a principal object of the present invention is to improve combustion in internal combustion engines that employ a nitrous oxide system.
A further object of the invention is to provide a nozzle design for a nitrous system that enhances atomization of the fuel and produce a more combustible mixture.
And a still further object of the invention is to provide a nitrous system nozzle that emits a jet or spray of finely divided liquid fuel into the nitrous oxide stream.
In accordance with the foregoing objects and advantages, the nitrous oxide system of the present invention includes a nitrous oxide emitting means for emitting a high velocity cylindrical stream of nitrous oxide from one location in a direction toward the intake manifold runner; and a fuel emitting means for emitting a thin fan shaped spray of atomized fuel from another location in another direction at an acute angle to the direction of the nitrous oxide stream. Both emitting means are oriented relative to one another so that the axes thereof form an acute angle there between and the stream of nitrous oxide and the thin fan shaped spray of fuel intersect at that acute angle at a location that is spaced from both emitting means in the direction of the intake manifold, wherein the high velocity stream of nitrous oxide impacts and further atomizes the fuel.
Further in accordance with the invention both emitting means comprise ports or outlets located on the same side of a nozzle. The nozzle contains a tip end for insertion inside the wall of the intake runner in the intake manifold of the internal combustion engine, and the fuel and nitrous oxide outlets are laterally spaced along and on the same side of the tip end, with the nitrous oxide outlet located closest to the distal or tip end of the nozzle.
Further in accordance with the invention, to produce the thin fan shaped mist or spray of atomized fuel, the fuel outlet is formed of a very thin slot. Fuel is pumped into the nozzle to that slot under a pressure within the range of five to eighty psig, with sixty psig being a preferred choice, recognizing that the higher the fuel pressure the better the atomization. In accordance with a more specific aspect to the invention, the acute angle between the nitrous oxide stream and the spray of fuel may be of a range of thirty-five to sixty degrees, with forty-five degrees being preferred.
The foregoing and additional objects and advantages of the invention, together with the structure characteristic thereof, which were only briefly summarized in the foregoing passages, will become more apparent to those skilled in the art upon reading the detailed description of a preferred embodiment of the invention, which follows in this specification, taken together with the illustrations thereof presented in the accompanying drawings.